This invention generally relates to a flight lug used in a conveyor system including one or more endless conveying belts for moving articles, and more particularly to a flight lug which is releasably fastened to a conveyor belt for selectively changing the position of, or replacing, the flight lug.
A conveyor system includes one or more continuous flexible conveyor belts movably supported on a framework. There are two general types of conveyor belts, chain belts and cord belts.Cord belts comprise polyurethane or similar suitable belt material surrounding fiber or steel cords. Cord belts are preferred over chain belts for high speed conveyor systems, or when cleanliness is a process requirement.
An array of spaced flight lugs are fixed along the length of a conveyor belt and project upwardly from the outer surface of the belt. The flight lugs are separated by a distance appropriate for individual articles being transported by the conveyor system, in effect, defining pockets which receive the articles. One or more flight lugs engage an article as the article is moved for properly positioning the articles on the conveyor belt and pushing the articles along in the direction of the path of travel.
Conventional flight lugs used on cord belts are formed from plastic. The plastic lugs are permanently welded, or vulcanized, directly onto the belt by melting the lug and the adjoining surface of the belt. However, vulcanized lugs are sometimes distorted which eventually results in tears at the edges of the belt. If a belt with welded plastic lugs is damaged or otherwise becomes jammed, the damaged lugs must be replaced in the field or the belt changed. Replacement of the lugs necessitates disassembly of the belt. This is a time consuming process resulting in significant labor costs and machine downtime, thereby increasing the overall cost associated with using a conventional conveyor system. Moreover, removal of a damaged lug that has been welded to the belt can damage the belt.
The pitch of a conveyor belt is determined by the space between the lugs. It is occasionally desirable to modify a conveying system for moving articles of different sizes, which requires changing the pitch of the belt. This is usually accomplished by moving the lugs toward or away from each other to accommodate smaller or larger articles, respectively. For example, a conveyor system running on a 12″ pitch at a speed of 1000 feet per minute moves 1000 pieces per minute. If the article being moved will allow a 6″ pitch, the conveyor system will move 2000 parts per minute with the belt running at the same speed. Unfortunately, since plastic lugs are permanently welded to the belt, the pitch of the belt cannot be easily changed. Therefore, a change in pitch requires that the belt be replaced by another belt with a different pitch.
For the foregoing reasons, there is a need for a flight lug which can be easily removed from a conveyor belt for repositioning or replacement to reduce the labor cost and machine downtime associated with a change in pitch or to repair a conveyor system. Ideally, the flight lugs should be adapted for use with a wide range of article configurations and sizes.